Ventilating system



April 1s, 1933. G. 'DE BOTHEZAT 1,903,983

VENTILATING SYSTEM Filed 00T.. 9, 1930 61002796' deoZ/egai f ToRNEYs 5 i E E lNvENToR EOl Patented Apr. 18, 1933 YUNITED STATESA GEORGE DE BOTHEZAT, OF NEW YORK,-N. Y.

VENTILATNG SYSTEM Applcationiled ctober 9, 1930. Serial No. 487,392.

This invention relates to forced'ventilation, and yparticularly to the ventilation of small enclosures such as telephone booths where it is important to renew the air without noise and while maintaining the booth in closed condition.

During use ot a telephone booth, when the door is generally closed, it is particularly import-ant to provide Ventilation without sacrifice of privacy and quietness.

The object of this invention is to provide a Ventilating system for telephone booths and the like wherein the Ventilating action will be noiseless and withoutrequiring any openingor modiiication of the enclosure rendering the users voice audible to those outside.

In the accompanying drawing illustrating the invention Fig. 1 is a perspective vie-w of a usual type of telephone booth showing the door closed and indicating a vertical positiontor the outlet of the Ventilating system,

Fig. 2 is a sectional view of the same show* ing. the boothwalls in outline, and

Fig. 3 is a diagrammatic view showing a modified arrangement of the Ventilating fan and outlet.

In the embodiment of the invention shown in the drawing a tele-phone booth B has the usual double walls comprising the side walls 5, G and ceiling walls 7, 8 and base 9 and door 10.

Attempts to ventilate such an enclosure by forcing air through a direct connection to the interior space S have been ineffective and have been objectionable in the resulting noise of the fan or other circulating means thus placed in direct communication with this interior.

I have found that thorough ventilation may be obtained with quietness and efficiency and Withoutimpairment of the privacy of the booth by indirectly using the area C between the double walls as an exhaust chamber, and in turn connecting this area to the interior space and relying on leakage into this interior space S to provide the air supply to the. booth.

For instance, an exhaust fan 12 driven by motor 13 forces air upward and outward thro-ugh opening 14 in the outer wall 8,'the motor tan unit being mounted in the frame 15 carried by flanges `16 generally fitting the opening through the outer wall. 'This structureV is such that the frame, motor and fan may be assembled Vin the opening from the outside and shock absorbing gaskets 17 of rubber or other soft material vInaybe vplaced between the frame 15 and the vwall 8 to avoid transmitting any of the motor vibrations to the walls of the booth.

Theexhaust action ofthe fan 12 lowers the pressure in the intermediate chamber C and openings 20 are provided between the interior space and the chamber C preferablyinv the ceiling wall 7 and out of direct alinement with the fan opening 14. The total area of the openings 20 is preferably greater than the area of the opening throughA the fan 12 so as to avoid excessive velocities of air in the openings 20. Through these openings20 the drop in pressure in the area C is transmitted to the interior space S, the air being drawn upwardly from above the breathing line.

To provide a supply of air for circulation, I have found that the usual leakage around the door 10 is sufficient particularly when, as is ordinarily the case,'therejis definite clearance between the bottom of the door 10 and the sill 19 and providing that the exhausting capacity of the fan 12 is not too great so as to cause excessive velocities of air through the door crevices. In practice I have lfound that a. disk fan of approximately 4 in diameter with avlarge central disk of one third or more of the diameter driven at a speed of approximately 1500 to 2000 R. P. M. will substantially renew the air within the ordi,- nary booth in about one minute, this fan 12 being of the disk typev described in my Patent No. 1,773,349. The motor 13 is about one hundredth of a horse power rating and consumes very little current indeed, and preterably is connectedin circuit with the usual light switch for the booth so that the fan is only run when the door-is closed.

The small power and low speed of the fanil2 make very noiseless in its action, and at the same tlme its e'iciency and ability to produce pressure give a very substantial reduction in the pressure within the area C. The openings 2O are sized and distributed so as to interfere with the whirr of the fan penetrating back to the space S within the booth, and preferably the ceiling wall 7 is made of sound insulating material. The clearance under the door should preferably be in the neighborhood of one eighth to one sixteenth of an inch to provide the main supply of air to the interior space S, the clearance at the top of the door being much smaller than at the bottom, and leakage also occurring along the vertical door joints at the sides and in the middle.

As shown in Fig. 3 the fan instead of being arranged vertically may be positioned horizontally in the attic space C, the distribution of the openings 20 being correspondingly changed to avoid any opening in direct line between the fan and the interior S. In each instance a protective screen 25 may be provided over the outlet from the fan.

In the system of this invention the small disk pressure fan discharging from the attic space at the top of the booth sucks air out of the space S through the holes or slots in the lower panel 8, these holes or slots being so disposed as to prevent any direct spreading of the noise from the fan into the booth space proper. There should be no slots or holes directly under the fan.

The renewal of the air in the space S is accomplished quietly and efiiciently, and without any increase in'outside audibility of the conversation of the user within the booth. The entering air passes at relatively high velocity under'the bottom of the door and through any other cracks or crevices providing leakage to this interior. Then the currents pass upward at very low velocity so as to be scarcely felt by the user until the openings 20 in the booth ceiling are reached, where the velocity is increased, but not to the point of whistling or being in anywise audible.V Then in the attic space the velocity again decreases and the currents of air turn and twist to pass on to the outlet lil where the fan rotor maintains a dierential pressure sufcient to draw air through'the entire system at a rate substantially renewing the air in the booth within oneminute. All of this is accomplished with an expenditure of a veryl small amountof power well within the one hundredth horse power rating of the motor. It is important that the booth door be ofthe ordinary type that does not tend to seal itself when the pressure is reduced in this space S, or if such a door were used, it would be necessary to provide other supply means for the air to the space S to prevent any undue reduction in the air pressure there- 1n.

I claim:

1. A telephone booth comprising inner and outer walls providing a space between them, an inner compartment enclosed by said inner walls, an upper enclosed chamber having an outer discharge opening provided with power driven means for exhausting air from said chamber so as to lower the pressure therein and an inner opening communicating with said inner compartment and acting to draw air therefrom above the breathing line so as to lower the pressure in said compartment, and-means providing a supply of air to the lower portion of said compartment below the breathing line, said openings in said chamber being arranged in staggered relation so as to be out of register with each other and sized to pass the air at velocities higher than the velocities through said compartment and chamber.

2. Ak telephone booth Ventilating system comprising ,innerv walls and a door enclosing an interior space for the user of the booth, an outer wall spaced from the inner .wall to provide an outer chamber and having an outlet opening, an exhaust means comprising av fan unit mounted on said outer wall and exhausting air at relatively high velocity through said opening in the outer wall to lower the pressure in said chamber and remove air therethrough at relatively low velocity, openings through which air passes at relatively high velocity between said outer chamber and said interior space above the breathing line of said space and out of line with the opening in the outer wall and connecting said chamber and space to lower the pressure in said space and renew air therein at relatively low velocity, and entrance means providing for supply of air to said space from the outside at relatively high velocity.

3. A telephone booth Ventilating system comprising inner walls and a door enclosing an interior space for the user of the booth, an outer wall spaced from the inner wall to provide an outer chamber and having an outlet opening and a disk fan exhausting air through said opening in the outer wall and acting to substantially lower the pressure in said chamber, a plurality of distributed holes between said outer chamber and said interior space above the breathing line of said space and located out of direct line with said exhaust fan and connecting said chamber and space to lower the pressure in said space, entrance means providing for supply of air to said space from the outside, and a motor driving said disk fan at a maximum peripheral speed of not more than three thousand feet per minute.

GEORGE DE BOTHEZAT. 

